The incidence of type 1 diabetes (T1D) in young children (age <5 years) is rising. The daily burden of responsibility for managing this disease largely falls to children's parents/caregivers to check blood sugar, administer insulin, and monitor diet and physical activity to achieve tight glycemic control. These tasks are complicated by children's unpredictable behaviors and erratic insulin levels, and ensuing parental stress. Thus, it is critical for the field of pediatric diabetes that we develop new behavioral interventios to better address glycemic control in this population. We will undertake this challenge, and develop and pilot test an innovative treatment program for parental management of T1D in young children. We propose to focus on promoting healthy eating and engagement in physical activity through the use of well-proven strategies with the general population. Delivery of the Type One Training (T.O.T.) intervention is expected to take place via phone and text message, in-clinic, and with lay parent consultants. The work will be carried-out in two phases. In Phase 1, primary caregivers of young children diagnosed with T1D will receive our draft version of T.O.T.s and be assessed post-intervention on indices of behavior and glycemic control. Participants will undergo formative interviews to provide rich, contextual data about thei experience in the program. Phase 1 findings will help drive intervention refinement and additional beta testing for Phase 2: where participants will be randomized to either a T.O.T.s (treatment) or usual care (control) condition. Intervention components are expected to include: parenting strategies specific to improving eating and physical activity behaviors, and T1D management support. These will be delivered across multiple modalities and change agents. Biomedical and psychosocial measurements (including HbA1c, physical activity, nutrition, mealtime behavior, pediatric parenting stress, quality of life) will occur at baseline and up to 6-months afterward. The results of this work will ultimately lead to a clinical behavioral treatment that may improve young children's T1D glycemic control and can be considered for further testing and clinical translation.